Also an only move by Arjun, as the queen needs to hit the h2-pawn as well as the g3-square.
8. d1d2 It seems as though the queen is positioned optimally here. 8... f6g4  9. f2f3  9... g4f2 This is what the line is all about. Carlsen needs to choose carefully. 10. c3a4 The only move.